They hate each other
(Book)

"There are plenty of words Jonah Collins could use to describe Dylan Ramírez. 'Arrogant,' 'spoiled,' and 'golden boy' to name a few. Likewise, Dylan thinks he has Jonah accurately labeled as an attention-seeking asshat who never shuts his filthy mouth. Their friends are convinced Jonah’s and Dylan’s disdain for one another is just thinly veiled lust—a rumor that surges like wildfire when the two wake up in one bed after homecoming. Mutually horrified, Dylan and Jonah agree to use the faux pas to their advantage by fake dating. If they can stay convincing long enough to end their 'relationship' in a massive staged fight, they can prove their incompatibility to their friends once and for all. But the more time they spend together, the more their plan begins to fall apart—and the closer they come to seeing each other clearly for the first time." --publisher's website.